UE communication handover between light fidelity access points in a communication system

ABSTRACT

A method by a coordination node is provided for controlling communications between Li-Fi APs and UEs. The method includes receiving peer connectivity reports from Li-Fi APs which identify Li-Fi APs having at least partially overlapping coverage areas, and developing a handover pathway data structure, based on the peer connectivity reports, that identifies Li-Fi APs that can receive communication handover from other identified Li-Fi APs. The method further includes determining an identifier of a first Li-Fi AP providing Li-Fi communication service for a UE, and accessing the handover pathway data structure using the identifier of the first Li-Fi AP to determine an identifier of a second Li-Fi AP to which handover from the first Li-Fi AP can be performed. The method then initiates handover of the Li-Fi communication service for the UE from the first Li-Fi AP to the second Li-Fi AP.

CROSS REFERENCE TO RELATED APPLICATION

This application is a 35 U.S.C. § 371 national stage application of PCTInternational Application No. PCT/EP2016/081559 filed on Dec. 16, 2016,the disclosure and content of which is incorporated by reference hereinin its entirety.

TECHNICAL FIELD

The present disclosure relates generally to networking systems andmethods and more particularly to Visible Light Communication (Li-Fi)systems and related Access Points (AP).

BACKGROUND

With the explosion of smart phones, tablets, laptops, and other userequipment (UE) both in enterprise (e.g., bring your own device or BYOD)and guest account scenarios, there is an ever increasing demand forwireless bandwidth in high density UE environments. WLAN (also referredto as Wireless Fidelity (WiFi)) has been a primary means of connectivityfor UEs. WLAN is generally defined in IEEE 802.11 and variants thereof.The wireless spectrum which is necessary for communication betweenWiFi/WLAN Access Points (APs) and UEs is becoming increasingly scarce asdemand grows exponentially with the proliferation of such devices.

Deploying more WiFi/WLAN Access Points (APs) may not be a right solutionbecause of already high levels of interference from competing devices.Many UEs support communication modes beyond WiFi, including utilizingsubscriber services provided by wireless service operators with 3G, 4GLong Term Evolution (LTE), and other communication protocols.Disadvantageously, connectivity through subscriber services can be morecostly and/or may provide lower bandwidth than WiFi. Accordingly, thereis a need for alternative systems and methods to providing wirelessbandwidth in high density UE environments.

Light Fidelity (Li-Fi) communication systems use the visible lightportion of the electromagnetic spectrum for communication between APsand UEs. Li-Fi may also be referred to as LiFi (Light WiFi). Li-Fi is analternative to a radio frequency based communications approach but canalso be prone to interference in some environments. Because Li-Fisignals are limited to line-of-sight and cannot penetrate walls andclosed doors, communication coverage areas provided by Li-Fi APs dependsupon the open space geometry of their rooms and can dynamically changeover time as signal blocking objects are remove and inserted. Theresulting potentially small and irregular geometric coverage areascomplicates technical approaches for providing mobility to usersoperating Li-Fi UEs.

SUMMARY

Some embodiments disclosed herein are directed to a method by acoordination node for controlling communications between Li-Fi APs andUEs. The method includes receiving peer connectivity reports from Li-FiAPs which identify Li-Fi APs having at least partially overlappingcoverage areas, and developing a handover pathway data structure, basedon the peer connectivity reports, that identifies Li-Fi APs that canreceive communication handover from other identified Li-Fi APs. Themethod further includes determining an identifier of a first Li-Fi APproviding Li-Fi communication service for a UE, and accessing thehandover pathway data structure using the identifier of the first Li-FiAP to determine an identifier of a second Li-Fi AP to which handoverfrom the first Li-Fi AP can be performed. The method then initiateshandover of the Li-Fi communication service for the UE from the firstLi-Fi AP to the second Li-Fi AP.

A potential advantage of this approach is that it can provide moreefficient and robust management of handover of UE communications betweenLi-Fi APs. The coordination node can use the peer connectivity reportsfrom the Li-Fi APs to dynamically update a handover pathway datastructure to track changes in the handover opportunities betweenparticular ones of the Li-Fi APs, such as when doors become open orclosed, when Li-Fi APs become powered on or power off, and/or when otherevents occur that change the communication capability of one or more ofthe Li-Fi APs. In view of the relatively small coverage areas providedby individual ones of the Li-Fi APs, developing and using a handoverpathway data structure as disclosed herein can enable handover decisionsto be quickly made based on the current availability of Li-Fi APs forhandover from particular other Li-Fi APs.

Some other related embodiments are directed to a coordination node forcontrolling communications between Li-Fi APs and UEs. The coordinationnode includes a receiving module, a handover pathway development module,a determining module, a handover pathway access module and a handovermodule. The receiving module is for receiving peer connectivity reportsfrom Li-Fi APs which identify Li-Fi APs having at least partiallyoverlapping coverage areas. The handover pathway development module isfor developing a handover pathway data structure, based on the peerconnectivity reports, that identifies Li-Fi APs that can receivecommunication handover from other identified Li-Fi APs. The determiningmodule is for determining an identifier of a first Li-Fi AP providingLi-Fi communication service for a UE. The handover pathway access moduleis for accessing the handover pathway data structure using theidentifier of the first Li-Fi AP to determine an identifier of a secondLi-Fi AP. The handover module is for initiating handover of the Li-Ficommunication service for the UE from the first Li-Fi AP to the secondLi-Fi AP.

Some other related embodiments are directed to another coordination nodefor controlling communications between Li-Fi APs and UEs. Thecoordination node includes a network interface, a processor coupled tothe network interface, and a memory coupled to the processor. The memorystores program code that when executed by the processor causes theprocessor to perform operations. The operations include receiving peerconnectivity reports from Li-Fi APs which identify Li-Fi APs having atleast partially overlapping coverage areas. The operations furtherinclude developing a handover pathway data structure, based on the peerconnectivity reports, that identifies Li-Fi APs that can receivecommunication handover from other identified Li-Fi APs. The operationsfurther include determining an identifier of a first Li-Fi AP providingLi-Fi communication service for a UE. The operations further includeaccessing the handover pathway data structure using the identifier ofthe first Li-Fi AP to determine an identifier of a second Li-Fi AP. Theoperations further include initiating handover of the Li-Ficommunication service for the UE from the first Li-Fi AP to the secondLi-Fi AP.

Other methods are directed to a Li-Fi AP for communicating with UEsunder control of a coordination node areas. The method includesreceiving Li-Fi signals from observed Li-Fi APs, where the Li-Fi signalsprovide identifiers of the observed Li-Fi APs. The method furtherincludes generating a peer connectivity report containing an identifierof the Li-Fi AP and the identifiers of the observed Li-Fi APs, andreporting the peer connectivity report to the coordination node.

Some other related embodiments are directed to a Li-Fi AP forcommunicating with UEs under control of a coordination node areas. TheLi-Fi AP includes a receiving module for receiving Li-Fi signals fromobserved Li-Fi APs, where the Li-Fi signals provide identifiers of theobserved Li-Fi APs. The Li-Fi AP further includes a report generatingmodule for generating (802) a peer connectivity report containing anidentifier of the Li-Fi AP and the identifiers of the observed Li-FiAPs, and a communication module for reporting the peer connectivityreport to the coordination node.

Some other related embodiments are directed to a Li-Fi AP forcommunicating with UEs under control of a coordination node areas, whichincludes a network interface, a processor coupled to the networkinterface, and a memory coupled to the processor. The memory storesprogram code that when executed by the processor causes the processor toperform operations. The operations include receiving Li-Fi signals fromobserved Li-Fi APs, where the Li-Fi signals provide identifiers of theobserved Li-Fi APs. The operations further include generating a peerconnectivity report containing an identifier of the Li-Fi AP and theidentifiers of the observed Li-Fi APs, and reporting the peerconnectivity report to the coordination node.

Other methods, coordination nodes, Li-Fi APs, and computer programproducts according to embodiments will be or become apparent to one withskill in the art upon review of the following drawings and detaileddescription. It is intended that all such additional methods,coordination nodes, Li-Fi APs, and computer program products be includedwithin this description and protected by the accompanying claims.

BRIEF DESCRIPTION OF THE DRAWINGS

Aspects of the present disclosure are illustrated by way of example andare not limited by the accompanying drawings. In the drawings:

FIG. 1 is a block diagram of a system that includes a coordination nodethat controls handover of UE communications between Li-Fi APs inaccordance with some embodiments of the present disclosure;

FIG. 2 illustrates Li-Fi APs to provide Li-Fi communication servicewithin a building, and for which a handover pathway data structure isdeveloped by the coordination node of FIG. 1, in accordance with someembodiments of the present disclosure;

FIG. 3a illustrates 7 Li-Fi APs spaced apart within 3 rooms which havean open pathway there between through which a user can transport a UE;

FIG. 3b graphically illustrates a handover pathway data structuredeveloped by the coordination node of FIG. 1 for use in controllinghandoff of UEs between the 7 Li-Fi APs of FIG. 3a , in accordance withsome embodiments of the present disclosure;

FIG. 4a illustrates the 7 Li-Fi APs of FIG. 3a but differs therefrombased on a door being closed between 2 of the adjacent rooms;

FIG. 4b graphically illustrates how the handover pathway data structureis modified to correspond to discovery of an absence of handoverconnectivity between the now closed-off 2 adjacent rooms, in accordancewith some embodiments of the present disclosure;

FIG. 5 is a combined data flow diagram and flowchart of operations bytwo Li-Fi APs to provide peer connectivity reports to the coordinationnode 110 for development of a handover pathway data structure inaccordance with some embodiments of the present disclosure;

FIG. 6 is a combined data flow diagram and flowchart of furtheroperations by the coordination node, the two Li-Fi APs, and the UE ofFIG. 5 to perform handover of the UE using the handover pathway datastructure in accordance with some embodiments of the present disclosure;

FIG. 7 is a flowchart of operations and methods by a coordination nodeto control the initiation of handover between Li-Fi APs and UEs inaccordance with some embodiments of the present disclosure;

FIGS. 8-11 are flowcharts of operations and methods by a Li-Fi AP togenerate peer connectivity reports that are sent to a coordination nodein accordance with some embodiments of the present disclosure;

FIG. 12 is a block diagram of a coordination node that is configuredaccording to some embodiments of the present disclosure;

FIG. 13 is a block diagram of modules forming a coordination node thatare configured according to some embodiments of the present disclosure;

FIG. 14 is a block diagram of a Li-Fi AP that is configured according tosome embodiments of the present disclosure; and

FIG. 15 is a block diagram of modules forming a Li-Fi AP that areconfigured according to some embodiments of the present disclosure.

DETAILED DESCRIPTION

Inventive concepts will now be described more fully hereinafter withreference to the accompanying drawings, in which examples of embodimentsof inventive concepts are shown. Inventive concepts may, however, beembodied in many different forms and should not be construed as limitedto the embodiments set forth herein. Rather, these embodiments areprovided so that this disclosure will be thorough and complete, and willfully convey the scope of various present inventive concepts to thoseskilled in the art. It should also be noted that these embodiments arenot mutually exclusive. Components from one embodiment may be tacitlyassumed to be present/used in another embodiment.

Li-Fi APs are anticipated to be used predominately indoors wherecommunication coverage areas can overlap in complex ways and wheremobility of UEs, such as while a user is walking down a hallway, cancomplicate the ability of such systems to maintain reliablecommunication links to such UEs. Embodiments of the present disclosureare directed to improving UE mobility between Li-Fi APs in environmentswhere some of the coverage areas can dynamically change due to, forexample, doors opening/closing and individual Li-Fi APs being switchedon/off.

FIG. 1 is a block diagram of a system that includes a coordination node110 that controls handover of UE communications between Li-Fi APs 130 inaccordance with some embodiments of the present disclosure. The Li-FiAPs 130 are connected to a wide area network (WAN) 150 through a localarea network (LAN) switch 140 via, e.g., a power line network through acommon power line, through Wi-Fi wireless RF connection, or otherwired/wireless connection. The Li-Fi APs 130 emit Li-Fi signals andreceive Li-Fi signals emitted by UEs 108, to provide communicationservices in their respective coverage areas. The Li-Fi signals may bewithin the visible light portion of the electromagnetic spectrum andencoded to communicate data between the UEs 108 and Li-Fi APs 130 forrouting through, e.g., the local area network (LAN) switch 140 and thewide area network (WAN) 150. In the illustrated example, spatiallyadjacent Li-Fi APs 130 have partially overlapping or nearly overlappingcoverage areas. The coordination node 110 operates to control handoverof UE communications between individual ones of the Li-Fi APs 130 tomaintain continuous or nearly continuous communication capability as aperson carries the UE 108 from the coverage area of one Li-Fi AP 130into the coverage area of another Li-Fi AP 130.

In accordance with various embodiments, handover between Li-Fi APs 130can be improved by the coordination node 110 developing a handoverpathway data structure which is used for handover of UE communicationsbetween the Li-Fi APs 130. The handover pathway data structure can beupdated over time to dynamically track changes that occur in theavailability of Li-Fi APs 130 for use in UE handover.

The coordination node 110 uses peer connectivity reports received fromthe Li-Fi APs 130 to develop the handover pathway data structure. Li-FiAPs 130 can generate the peer connectivity reports based on identifyingfrom which, if any, other Li-Fi APs 130 it receives Li-Fi signals. Thepeer connectivity reports can be generated to contain informationidentifying the other Li-Fi APs 130. The handover pathway data structurecan be retained in memory of a repository 120. Li-Fi APs 130 mayperiodically share their peer connectivity reports with other observableLi-Fi APs 130 through Li-Fi signaling or other communication signalingtherebetween. A Li-Fi AP 130 can use a peer connectivity report fromanother Li-Fi AP 130 to update its local peer connectivity information,and which it can use to generate the peer connectivity reports.

As will be explained in further detail below, handover between Li-Fi APs130 can be initiated by the coordination node 110 in response adetermination that a communication signal quality measurement, e.g.,signal strength and/or bit error rate, has dropped below a definedquality threshold. Comparison of the communication signal qualitymeasurement to the defined quality threshold may be performed by the UE108 based on a Li-Fi signal received from a Li-Fi AP 130, by the Li-FiAP 130 based on a Li-Fi signal received from the UE 108, and/or by thecoordination node 110 based on receipt of the communication signalquality measurement from the Li-Fi AP 130.

FIG. 2 illustrates Li-Fi APs 130 that are spaced apart to provide Li-Ficommunication coverage areas in various rooms and hallways within abuilding. Referring to FIG. 2 it is observed that some of the Li-Fi APs130 have partially overlapping coverage areas because they can emit andreceive Li-Fi signals passing through various door and other openingsbetween the rooms, hallways, stairwells, etc. between adjacent coverageareas. The connection node 110 of FIG. 1 is configured to initiatehandover between the Li-Fi APs 130 of ongoing Li-Fi communications witha UE as a person transports the UE throughout the building. Theconnection node 110 develops a handover pathway data structure for thebuilding, which it uses to carry out initiation of handover.

FIG. 3a illustrates 7 Li-Fi APs (named A-E, G, H) spaced apart within 3rooms (Rooms 101, 102, 103) which have an open pathway between theadjacent rooms, and through which a user can transport a UE. FIG. 3bgraphically illustrates an example handover pathway data structuredeveloped by the coordination node 110 of FIG. 1 for use in controllinghandoff of UEs between the 7 Li-Fi APs of FIG. 3a . The example handoverpathway data structure contains information identifying that Li-Fi AP(A) can handoff to Li-Fi APs (B), (C), and (D); Li-Fi AP (D) can handoffto Li-Fi APs (A) and (E); and Li-Fi AP (E) can handoff to Li-Fi APs (G)and (H). Thus, for example, when a handover condition becomes satisfiedfor an ongoing Li-Fi communication service for a UE, e.g., such as whena UE signal quality measurement drops below a quality threshold, thecoordination node 110 accesses the handover pathway data structure usingthe identifier of the current Li-Fi AP to determine an identifier of oneor more other Li-Fi APs to which the Li-Fi communication service for theUE can be handed over. The coordination node then initiates handover ofthe Li-Fi communication service for the UE from the current Li-Fi AP tothe identified one or more other Li-Fi APs or to a further selected oneof a plurality of the available Li-Fi APs. The quality threshold maycorrespond to any one or more of: a signal strength threshold, a biterror rate threshold, etc.

Further example operations are now explained in view of the coveragescenario of FIG. 3b . As a UE is transported from the coverage area ofLi-Fi AP (A) into the coverage area of Li-Fi AP (B), the signal strengthmeasurements by the UE of Li-Fi signals from the Li-Fi AP (A) will fallbelow a signal strength threshold. The UE can report the signal strengthmeasurements through one or both of the Li-Fi APs (A) and (B) to thecoordination node 110. The coordination node 110 accesses the handoverpathway data structure to determine that handover from Li-Fi AP (A) toLi-Fi AP (B), Li-Fi AP (C), and Li-Fi AP (D) is allowed. In oneembodiment, the coordination node 110 can initiate handover of theongoing Li-Fi communication service for the UE from Li-Fi AP (A) to thegroup of Li-Fi APs (B), (C), and (D). In a further embodiment, thecoordination node 110 selects Li-Fi AP (B) as a best candidate among thegroup of available Li-Fi APs, and responsively initiates handover of theongoing Li-Fi communication service for the UE from Li-Fi AP (A) toLi-Fi AP (B).

Further related operations are explained in the context of as the UE istransported from the coverage area of Li-Fi AP (A) into the coveragearea of Li-Fi AP (D), the UE can report signal strength measurementsindicating that Li-Fi signals received from Li-Fi AP (A) have fallenbelow the signal strength threshold while signal strength measurementsof Li-Fi signals received from Li-Fi AP (D) have risen above the signalstrength threshold. The reported measurements can trigger thecoordination node 110 to determine from the handover pathway datastructure that handover from Li-Fi AP (A) to Li-Fi AP (D) is allowedand, responsively, initiate handover of the ongoing Li-Fi communicationservice for the UE from Li-Fi AP (A) to Li-Fi AP (D).

FIG. 4a illustrates the 7 Li-Fi APs of FIG. 3a but differs therefrombased on a door being closed between adjacent rooms 101 and 102, therebypreventing Li-Fi AP (A) from receiving Li-Fi signals from Li-Fi AP (D)and vice versa. Other events that can cause Li-Fi APs to no longerreceive Li-Fi signal from one another, can include becoming powered-off,becoming inoperative to emit Li-Fi signals, becoming inoperative toreceive Li-Fi signals, etc. FIG. 4b graphically illustrates how theexample handover pathway data structure has been developmentallymodified by the coordination node 110 responsive to discovering, throughone or more peer connectivity reports received from Li-Fi AP (A) and/orLi-Fi AP (D), that Li-Fi AP (A) can no longer detect Li-Fi signals fromLi-Fi AP (D) or vice versa. Information contained in the examplehandover pathway data structure of FIG. 3b is therefore modified by thecoordination node 110 so that Li-Fi AP (A) is no longer indicated inFIG. 4b as having the ability to handoff to Li-Fi AP (D) and vice versa.

Further example operations are explained in view of the coveragescenario of FIG. 4b , as a UE is transported from the coverage area ofLi-Fi AP (A) into the coverage area of Li-Fi AP (B), the signal strengthmeasurements by the UE of Li-Fi signals from the Li-Fi AP (A) will fallbelow a signal strength threshold. The UE can report the signal strengthmeasurements through one or both of the Li-Fi APs (A) and (B) to thecoordination node 110. The coordination node 110 accesses the handoverpathway data structure and determines that handover from Li-Fi AP (A) toLi-Fi AP (B) and Li-Fi AP (C) is allowed. In one embodiment, thecoordination node 110 can initiate handover of the ongoing Li-Ficommunication service for the UE from Li-Fi AP (A) to the group of Li-FiAPs (B) and (C). In contrast to the example of FIG. 3b , thecoordination node 110 does not initiate handover of the ongoing Li-Ficommunication service to the Li-Fi AP (D) because that AP is notindicated to be presently available for handover from Li-Fi AP (A).

In this manner, when a peer connectivity report from a Li-Fi AP 130indicates that it has received signals from another Li-Fi AP 130, thecoordination node 110 determines that the two Li-Fi APs 130 have atleast partially overlapping coverage areas and responsively updates thecorresponding handover information for those Li-Fi APs 130 in thehandover pathway data structure. The coordination node 110 can similarlyupdate the corresponding handover information for those Li-Fi APs 130 inthe handover pathway data structure to indicate when those Li-Fi APs 130are no longer indicated by the peer connectivity reports to be able toreceive signals from each other. The coordination node 110 therebylearns over time and updates the handover pathway data structure toindicate which Li-Fi APs 130 have at least partially overlappingcommunication coverage areas and can be used for performing handover ofLi-Fi communication service for UEs.

FIG. 5 is a combined data flow diagram and flowchart of operations bytwo Li-Fi APs (first and second Li-Fi APs) to provide peer connectivityreports to the coordination node 110 for development of a handoverpathway data structure in accordance with some embodiments of thepresent disclosure. FIG. 6 is a combined data flow diagram and flowchartof further operations by the coordination node 110, the first and secondLi-Fi APs, and the UE 108 of FIG. 5 to perform handover of the UE 108using the handover pathway data structure in accordance with someembodiments of the present disclosure. FIG. 7 is a flowchart ofoperations and methods by the coordination node 110 to control theinitiation of handover between Li-Fi APs 130 and UEs 108 in accordancewith some embodiments of the present disclosure. FIGS. 8-11 areflowcharts of operations and methods by the Li-Fi APs 130 to generatepeer connectivity reports that are sent to the coordination node 110 inaccordance with some embodiments of the present disclosure.

Various operations that can be performed by the Li-Fi APs 130 togenerate peer connectivity reports for communication to the coordinationnode 110, and by the coordination node 110 to develop a handover pathwaydata structure therefrom are now explained in the context of FIGS. 5 and8. The second Li-Fi AP 130 receives (block 500 of FIG. 5, block 800 ofFIG. 8) a Li-Fi signal from the first Li-Fi AP 130. The Li-Fi signalprovides an identifier of the first Li-Fi AP 130. The second Li-Fi AP130 generates (block 802) a peer connectivity report containing anidentifier of the Li-Fi AP 130 and the identifier of the first Li-Fi APs130. When the second Li-Fi AP 130 receives Li-Fi signals from otherobservable Li-Fi APs 130, it generates the peer connectivity report tofurther contain identifiers of each of the observable Li-Fi APs 130. Thesecond Li-Fi APs 130 reports (blocks 502 and 804) the peer connectivityreport to the coordination node 110. The operations of second Li-Fi AP130 within dashed box 510 can be similarly performed by the first Li-FiAP 130 responsive to Li-Fi signals received from the second Li-Fi AP 130and any other observable Li-Fi APs 130, to communicate a peerconnectivity report to the coordination node 110.

The coordination node 110 uses the received peer connectivity reports todevelop (block 504) a handover pathway data structure. Exampleoperations that may be performed by the coordination node 110 to developthe handover data structure are shown in FIG. 7. With further referenceto FIG. 7, the coordination node 110 receives (blocks 502 and 700) peerconnectivity reports from Li-Fi APs 130 which identify Li-Fi APs havingat least partially overlapping coverage areas, i.e., based on the Li-FiAPs receiving signals from other Li-Fi APs. The coordination node 110develops (blocks 504 and 702) the handover pathway data structure, basedon the peer connectivity reports, that identifies Li-Fi APs 130 that canreceive communication handover from other identified Li-Fi APs 130. Thecoordination node 110 may store the handover pathway data structure inmemory of the repository 120.

In one embodiment, operations to develop (blocks 504 and 702) thehandover pathway data structure, include determining an identifier of areporting Li-Fi AP 130 (i.e., the first Li-Fi AP) that reported one ofthe peer connectivity reports to the coordination node 110, determiningan identifier of one or more observed Li-Fi APs 130 (i.e., the secondLi-Fi AP) based on content of the one of the peer connectivity reports,and storing in the handover pathway data structure the identifier of theone or more observed Li-Fi APs 130 (i.e., the second Li-Fi AP) with alogical association to the identifier of the reporting Li-Fi AP 130(i.e., the first Li-Fi AP). Operations to determine (blocks 604 and 704)an identifier of a first Li-Fi AP 130 providing Li-Fi communicationservice for the UE 108, can include receiving (e.g., signaling 600 inFIG. 6) a report containing a measurement by the UE 108 of a Li-Fisignal transmitted by the first Li-Fi AP 130, and responsive todetermining that the measurement does not satisfy a signal qualitythreshold, performing the initiating handover (blocks 608 and 708) ofthe Li-Fi communication service for the UE 108 from the first Li-Fi AP130 to the second Li-Fi AP 130.

The coordination node 110 may receive Li-Fi signal measurements reportedby the Li-Fi APs 130, and use the signal measurements to determinewhether to update the handover pathway data structure based on the Li-FiAPs 130 identified in the reports. For example, when a peer connectivityreport from the first Li-Fi AP 130 contains a measurement of a signalreceived from the second Li-Fi AP 130 that is determined to be less thana signal quality threshold, the coordination node 110 may choose not toadd the second Li-Fi AP 130 to the handover pathway data structure sinceit should not be an allowable candidate for handover from the firstLi-Fi AP 130. Moreover, when the handover pathway data structurepresently lists the second Li-Fi AP 130 as an allowable candidate forhandover from the first Li-Fi AP 130 and the received signal measurementis less than the signal quality threshold, the coordination node 110 mayremove the second Li-Fi AP 130 from the listing associated with thefirst Li-Fi AP 130 since it should no longer be an allowable candidatefor handover from the first Li-Fi AP 130.

Related illustrative operations can include generating the peerconnectivity reports to contain pairs of an identifier of one of the oneor more observed Li-Fi APs 130 and a measurement by the reporting Li-FiAP 130 of a Li-Fi signal received from the one of the one or moreobserved Li-Fi APs 130. Referring to the operations shown in FIG. 11, aLi-Fi AP 130 measures (block 1100) the Li-Fi signals received fromobserved Li-Fi APs 130, and generates (block 1102) a peer connectivityreport to contain the measurements with defined associations to theidentifiers of the observed Li-Fi APs 130.

The coordination node 110 can selectively perform storing in thehandover pathway data structure of the identifier of the observed Li-FiAP 130 with a logical association to the identifier of the reportingLi-Fi AP 130, only if the measurement by the reporting Li-Fi AP 130 ofthe Li-Fi signal received from the one of the one or more observed Li-FiAPs 130 satisfies a signal quality threshold.

The handover pathway data structure may be selectively updated only ifthe received signal measurement indicates that a signal strengththreshold is satisfied and/or that a bit error rate threshold issatisfied. In one further embodiment, the identifier of the one of theone or more observed Li-Fi APs 130 is selectively stored in the handoverpathway data structure with a logical association to the identifier ofthe reporting Li-Fi AP 130, only if a signal strength indicated by themeasurement satisfies a signal strength threshold. In an alternative oradditional further embodiment, the identifier of the one of the one ormore observed Li-Fi APs 130 is selectively stored in the handoverpathway data structure with a logical association to the identifier ofthe reporting Li-Fi AP 130, only if a bit error rate indicated by themeasurement satisfies a bit error rate threshold.

The signal measurements reported by a Li-Fi AP 130 can be used to selecta particular Li-Fi AP 130 from among a group of candidate Li-Fi APs 130for use in initiating handover. At least some of the peer connectivityreports received by the coronation node 110 can contain pairs of anidentifier of an observed Li-Fi APs 130 and a measurement by thereporting Li-Fi AP 130 of a Li-Fi signal received from the observedLi-Fi APs 130. The coordination node 110 can store the pairs in thehandover pathway data structure with a logical association to theidentifier of the reporting Li-Fi AP 130. The coordination node's 110access (blocks 606 and 706) of the handover pathway data structure usingthe identifier of the first Li-Fi AP 130 can therefore identify aplurality of candidate Li-Fi APs 130. The coordination node 110 canselect the second Li-Fi AP 130 from among the candidate Li-Fi APs 130based on comparison of the measurements associated with the candidateLi-Fi APs 130 which are retrieved from the handover pathway datastructure.

The coordination node 110 can further update the handover pathway datastructure to remove a particular Li-Fi AP 130 from being associated witha reporting Li-Fi AP 130 when it becomes absent for threshold elapsedtime from peer connectivity reports received from the reporting Li-Fi AP130. Accordingly, the operations performed by the coordination node 110to develop (blocks 504 and 702) the handover pathway data structure caninclude the following operations. Subsequent to storing an identifier ofan observed Li-Fi AP with a logical association to an identifier of areporting Li-Fi AP in the handover pathway data structure, thecoordination node 110 can determine that an absentee one of the observedLi-Fi APs 130 has not been identified in a peer connectivity reportreceived from the reporting Li-Fi AP 130 in at least a threshold elapsedtime. The coordination node can responsively remove from the handoverpathway data structure the identifier of the absentee one of theobserved Li-Fi APs 130 and its logical association to the identifier ofthe reporting Li-Fi AP 130.

Corresponding operations by a Li-Fi AP 130 and include subsequent to areporting of the peer connectivity report to the coordination node 110,determining that a Li-Fi signal has not been received from one of theobserved Li-Fi APs 130 contained in the peer connectivity report in atleast a threshold elapsed time, and excluding the one of the observedLi-Fi APs 130 from another peer connectivity report that is nextreported to the coordination node 110 responsive to the determination.Thus, the Li-Fi AP 130 can selectively include identifiers for variouspreviously observed Li-Fi APs 130 depending upon whether the Li-Fi AP130 has received a Li-Fi signal therefrom within the threshold elapsedtime.

Responsive to a determination that handover of Li-Fi communicationservice for the UE 108 is needed or responsive to another defined event,the coordination node 110 determines (block 704) an identifier of thefirst Li-Fi AP 130 providing Li-Fi communication service for the UE 108,and accesses (block 706) the handover pathway data structure using theidentifier of the first Li-Fi AP 130 to determine an identifier of asecond Li-Fi AP 130 to which handover from the first Li-Fi AP 130 can beperformed. The coordination node 110 then initiates handover (block 708)of the Li-Fi communication service for the UE 108 from the first Li-FiAP 130 to the second Li-Fi AP 130.

A potential advantage of this approach is that it can provide moreefficient and robust management of handover of UE communications betweenLi-Fi APs 130. The coordination node 110 can use the peer connectivityreports from the Li-Fi APs 130 to dynamically update a handover pathwaydata structure to track changes in the handover opportunities betweenparticular ones of the Li-Fi APs 130, such as when doors become open orclosed, when Li-Fi APs 130 become powered on or power off, and/or whenother events occur that change the communication capability of one ormore of the Li-Fi APs 130. In view of the relatively small coverageareas provided by individual ones of the Li-Fi APs, developing and usinga handover pathway data structure as disclosed herein can enablehandover decisions to be quickly made based on the current availabilityof Li-Fi APs for handover from particular other Li-Fi APs.

Further operations that can be performed by the Li-Fi APs 130 and thecoordination node 110 to trigger and perform handover, are now describedin the context of FIGS. 6 and 9-11.

In the operational scenario of FIG. 5, the first Li-Fi AP 130 isproviding Li-Fi communication service to the UE 108. The first Li-Fi AP130 may perform signal measurements on Li-Fi signals received from theUE 108 and/or may receive signal measurements performed by the UE 108 onLi-Fi signals received from the first Li-Fi AP 130 and/or otheridentified Li-Fi APs, such as the second Li-Fi AP 130.

In some embodiments, handover decisions are performed by thecoordination node 110 using signal measurements reported by the variousLi-Fi APs 130. In the example operations of FIG. 6, the first Li-Fi AP130 can report (block 602) signal measurements to the coordination node110. The signal measurements may be performed by the first Li-Fi AP 130and/or by the UE 108. According to the operational embodiment of FIG. 9,the first Li-Fi AP 130 measures (block 900) a Li-Fi signal received fromthe UE (108) during Li-Fi communication service by the first Li-Fi AP130 for the UE (108), and includes (block 902) an indication of themeasurement in the peer connectivity report reported to the coordinationnode 110. Alternatively or additionally, the first Li-Fi AP 130 receives(block 602) from the UE 108 measurements by the UE 108 of Li-Fi signalstransmitted by the first Li-Fi AP 130 and/or received from other Li-FiAPs 130, such as from the second Li-Fi AP 130. The first Li-Fi AP 130responsively reports (blocks 502, 602, 804) an indication of themeasurements in the peer connectivity report. The measurements mayalternatively or additionally be communicated in reporting messages thatare separate from the peer connectivity reports.

In some other embodiments, handover decisions are performed by the Li-FiAPs 130 using signal measurements received from UEs 108 and/or usingsignal measurements they perform on Li-Fi signals received from UEs 108.In the embodiment of FIG. 6, the first Li-Fi AP 130 compares signalmeasurements, received from a UE 108 and/or performed on Li-Fi signalsreceived from the UE 108, to a signal quality threshold. Responsive tothe signal measurement not satisfying the signal quality threshold, thefirst Li-Fi AP 130 sends a handover request message to the coordinationnode 110, where the handover request message contains an identifier ofthe first Li-Fi AP may further contain an identifier of the UE 108.

The coordination node 110 determines (blocks 604 of FIG. 6 and 704 ofFIG. 7) an identifier of the first Li-Fi AP 130 providing Li-Ficommunication service for the UE 108. The coordination node 110 maydetermine (blocks 604 and 704) the identifier of the first Li-Fi AP 130by operations that include parsing the handover request message receivedfrom the first Li-Fi AP 130 to determine the identifier of the firstLi-Fi AP 130.

The coordination node 110 accesses (blocks 606 and 706) the handoverpathway data structure using the identifier of the first Li-Fi AP 130 todetermine an identifier of a second Li-Fi AP 130 to which handover fromthe first Li-Fi AP 130 can be performed, and initiates handover (blocks608 and 708) of the Li-Fi communication service for the UE 108 from thefirst Li-Fi AP 130 to the second Li-Fi AP 130 that is identified. Thesecond Li-Fi AP 130 subsequently operates to provide (block 610) Li-Ficommunication service for the UE 108, and which may or may not beperformed without interruption of a flow of data packets to the UE 108.

Operations by the coordination node 110 to initiate handover (blocks 608and 708) can include initiating re-routing of data packets that areaddressed to the UE 108, to be directed to the second Li-Fi AP 130instead of to the first Li-Fi AP 130. Such data packet rerouting may beinitiated by the coordination node 110 sending instructions to the LANswitch 140. Alternative or additional operations by the coordinationnode 110 to initiate handover can include sending a handover message tothe first Li-Fi AP 130 that contains both the address of the UE 108 andthe identifier of the second Li-Fi AP 130 to which the handover is beingperformed.

Operations by the first Li-Fi AP 130 for performing handover accordingto one embodiment is shown in FIG. 10. The first Li-Fi AP 130 receives(block 1000) the handover message, and responsively performs (block1002) handover of the Li-Fi communication service for the identified UE108 from the first Li-Fi AP 130 to the second Li-Fi AP 130 that isidentified in the handover message. In still another embodiment, thefirst Li-Fi AP 130 can receive the handover message, and responsivelyforward the handover message to the UE 108 to trigger the UE 108 toinitiate handover of the Li-Fi communication service from the firstLi-Fi AP 130 to the second Li-Fi AP 130.

Although various embodiments have been explained in which thecoordination node 110 directly controls operation of the first andsecond Li-Fi APs 130, in some other embodiments the coordination node110 operates to coordinate negotiations between the Li-Fi APs 130. Thecoordination node 110 may operate to coordinate negotiations between thefirst and second Li-Fi APs 130 to perform the handover of the Li-Ficommunication service for the UE 108. Accordingly, decentralizedhandover decision-making can be performed by the various Li-Fi APs 130instead of via centralized handover decision-making by the coordinationnode 110. The ordination node 110 may communicate handover relatedinformation, obtained from its accessing (blocks 606 and 706) of thehandover pathway data structure, to the first Li-Fi AP 130 and/or thesecond Li-Fi AP 130 to enable their negotiation of handover of Li-Ficommunication service for the UE 108. The negotiations may be performedusing negotiation messaging that is communicated through the interveningcoordination node 110 and/or that is communicated directly between theLi-Fi APs 130.

In a situation when the coordination node 110 does not identify aparticular Li-Fi AP 130 from the handover pathway data structure thatcan be used for handover, the coordination node 110 may responsivelyinitiate handover to a group of Li-Fi APs 130. In one embodiment,responsive to the accessing (blocks 606 and 706) of the handover pathwaydata structure resulting in return of no identifier of another Li-Fi AP130 as having been defined as associated with the identifier of thefirst Li-Fi AP 130, the coordination node 110 initiates handover (blocks608 and 708) of the Li-Fi communication service for the UE 108 from thefirst Li-Fi AP 130 to a group of Li-Fi APs 130 at least one of whichthat is likely to have a coverage area that includes the UE 108. Forexample, the coordination node 110 may be configured to initiatere-routing of data packets for the UE 108 to all Li-Fi APs within adefined graphic area of the first Li-Fi AP 130, such as all Li-Fi APshave been defined to be proximately located to the first Li-Fi AP 130.For example, as explained above regarding FIG. 3b , when a UE beingserviced by Li-Fi AP (A) is carried away from that service area, thecoordination node 110 may responsively initiate handover ofcommunication service for the UE to a group of Li-Fi APs (B), (C), and(D).

FIG. 12 is a block diagram of the coordination node 110 that isconfigured according to some embodiments of the present disclosure. Thecoordination node 110 includes a processor 1200, a memory 1210, and anetwork interface circuit which may include Li-Fi network transceivercircuit 1226, and/or may include a radio and/or wired network interface1224 (e.g., Ethernet interface). The radio network interface 1224 caninclude, but is not limited to, a LTE or other cellular transceiver,WiFi transceiver (IEEE 802.11), Bluetooth, WiMax transceiver, or otherwireless communication transceiver configured to communicate with theLi-Fi APs 130.

The processor 1200 may include one or more data processing circuits,such as a general purpose and/or special purpose processor (e.g.,microprocessor and/or digital signal processor) that may be collocatedor distributed across one or more networks. The processor 1200 isconfigured to execute computer program code 1212 in the memory 1210,described below as a non-transitory computer readable medium, to performat least some of the operations described herein as being performed by acoordination node. The memory 1210 may further include the Li-Fi APhandover pathway data structure repository 120. The coordination node110 may further include a user input interface 1220 (e.g., touch screen,keyboard, keypad, etc.) and a display device 1222.

FIG. 13 is a block diagram of modules 1300 forming a coordination nodethat is configured according to some embodiments of the presentdisclosure. Referring to FIG. 13, the modules 1300 include a receivingmodule 1300, a handover pathway development module 1302, a determiningmodule 1304, a handover pathway access module 1306, and a handovermodule 1308. The receiving module 1300 is for receiving (block 502 and700) peer connectivity reports from Li-Fi APs 130 which identify Li-FiAPs having at least partially overlapping coverage areas. The handoverpathway development module 1302 is for developing (blocks 504 and 702) ahandover pathway data structure, based on the peer connectivity reports,that identifies Li-Fi APs 130 that can receive communication handoverfrom other identified Li-Fi APs 130. The determining module 1304 is fordetermining (blocks 604 and 704) an identifier of a first Li-Fi AP 130providing Li-Fi communication service for a UE 108. The handover pathwayaccess module 1306 is for accessing (blocks 606 and 706) the handoverpathway data structure using the identifier of the first Li-Fi AP 130 todetermine an identifier of a second Li-Fi AP 130. The handover module1308 is for initiating handover (blocks 608 and 708) of the Li-Ficommunication service for the UE 108 from the first Li-Fi AP 130 to thesecond Li-Fi AP 130.

FIG. 14 is a block diagram of a Li-Fi AP 130 that is configuredaccording to some embodiments of the present disclosure. The Li-Fi AP130 includes a processor 1400, a memory 1410, a Li-Fi transceivercircuit 1420, and may further include a wired network interface 1422(e.g., Ethernet) and/or a radio network transceiver circuit 1424. TheLi-Fi transceiver circuit 1420 is configured to communicate with UEs 108according to or more embodiments herein. The radio network transceivercircuit 1424 can include, but is not limited to, a LTE or other cellulartransceiver, WIFI transceiver (IEEE 802.11), Bluetooth, WiMaxtransceiver, or other wireless communication transceiver configured tocommunicate with the coordination node 110.

The processor 1400 may include one or more data processing circuits,such as a general purpose and/or special purpose processor (e.g.,microprocessor and/or digital signal processor) that may be collocatedor distributed across one or more networks. The processor 1400 isconfigured to execute computer program code 1412 in the memory 1410,described below as a non-transitory computer readable medium, to performat least some of the operations described herein as being performed by aLi-Fi AP.

FIG. 15 is a block diagram of modules 1300 forming a Li-Fi AP that isconfigured according to some embodiments of the present disclosure.Referring to FIG. 15, the modules 1500 include a receiving module 1500,a report generating module 1502, and a communication module 1504. Thereceiving module is for receiving (blocks 500 and 800) Li-Fi signalsfrom observed Li-Fi APs 130, where the Li-Fi signals provide identifiersof the observed Li-Fi APs 130. The report generating module 1502 is forgenerating (block 802) a peer connectivity report containing anidentifier of the Li-Fi AP 130 and the identifiers of the observed Li-FiAPs 130. The communication module 1504 is for reporting (blocks 502 and804) the peer connectivity report to the coordination node (110).

Further Definitions and Embodiments

In the above-description of various embodiments of present inventiveconcepts, it is to be understood that the terminology used herein is forthe purpose of describing particular embodiments only and is notintended to be limiting of present inventive concepts. Unless otherwisedefined, all terms (including technical and scientific terms) usedherein have the same meaning as commonly understood by one of ordinaryskill in the art to which present inventive concepts belongs. It will befurther understood that terms, such as those defined in commonly useddictionaries, should be interpreted as having a meaning that isconsistent with their meaning in the context of this specification andthe relevant art and will not be interpreted in an idealized or overlyformal sense expressly so defined herein.

When an element is referred to as being “connected”, “coupled”,“responsive”, or variants thereof to another element, it can be directlyconnected, coupled, or responsive to the other element or interveningelements may be present. In contrast, when an element is referred to asbeing “directly connected”, “directly coupled”, “directly responsive”,or variants thereof to another element, there are no interveningelements present. Like numbers refer to like elements throughout.Furthermore, “coupled”, “connected”, “responsive”, or variants thereofas used herein may include wirelessly coupled, connected, or responsive.As used herein, the singular forms “a”, “an” and “the” are intended toinclude the plural forms as well, unless the context clearly indicatesotherwise. Well-known functions or constructions may not be described indetail for brevity and/or clarity. The term “and/or” includes any andall combinations of one or more of the associated listed items.

It will be understood that although the terms first, second, third, etc.may be used herein to describe various elements/operations, theseelements/operations should not be limited by these terms. These termsare only used to distinguish one element/operation from anotherelement/operation. Thus a first element/operation in some embodimentscould be termed a second element/operation in other embodiments withoutdeparting from the teachings of present inventive concepts. The samereference numerals or the same reference designators denote the same orsimilar elements throughout the specification.

As used herein, the terms “comprise”, “comprising”, “comprises”,“include”, “including”, “includes”, “have”, “has”, “having”, or variantsthereof are open-ended, and include one or more stated features,integers, elements, steps, components or functions but does not precludethe presence or addition of one or more other features, integers,elements, steps, components, functions or groups thereof. Furthermore,as used herein, the common abbreviation “e.g.”, which derives from theLatin phrase “exempli gratia,” may be used to introduce or specify ageneral example or examples of a previously mentioned item, and is notintended to be limiting of such item. The common abbreviation “i.e.”,which derives from the Latin phrase “id est,” may be used to specify aparticular item from a more general recitation.

Example embodiments are described herein with reference to blockdiagrams and/or flowchart illustrations of computer-implemented methods,apparatus (systems and/or devices) and/or computer program products. Itis understood that a block of the block diagrams and/or flowchartillustrations, and combinations of blocks in the block diagrams and/orflowchart illustrations, can be implemented by computer programinstructions that are performed by one or more computer circuits. Thesecomputer program instructions may be provided to a processor circuit ofa general purpose computer circuit, special purpose computer circuit,and/or other programmable data processing circuit to produce a machine,such that the instructions, which execute via the processor of thecomputer and/or other programmable data processing apparatus, transformand control transistors, values stored in memory locations, and otherhardware components within such circuitry to implement thefunctions/acts specified in the block diagrams and/or flowchart block orblocks, and thereby create means (functionality) and/or structure forimplementing the functions/acts specified in the block diagrams and/orflowchart block(s).

These computer program instructions may also be stored in a tangiblecomputer-readable medium that can direct a computer or otherprogrammable data processing apparatus to function in a particularmanner, such that the instructions stored in the computer-readablemedium produce an article of manufacture including instructions whichimplement the functions/acts specified in the block diagrams and/orflowchart block or blocks. Accordingly, embodiments of present inventiveconcepts may be embodied in hardware and/or in software (includingfirmware, resident software, micro-code, etc.) that runs on a processorsuch as a digital signal processor, which may collectively be referredto as “circuitry,” “a module” or variants thereof.

It should also be noted that in some alternate implementations, thefunctions/acts noted in the blocks may occur out of the order noted inthe flowcharts. For example, two blocks shown in succession may in factbe executed substantially concurrently or the blocks may sometimes beexecuted in the reverse order, depending upon the functionality/actsinvolved. Moreover, the functionality of a given block of the flowchartsand/or block diagrams may be separated into multiple blocks and/or thefunctionality of two or more blocks of the flowcharts and/or blockdiagrams may be at least partially integrated. Finally, other blocks maybe added/inserted between the blocks that are illustrated, and/orblocks/operations may be omitted without departing from the scope ofinventive concepts. Moreover, although some of the diagrams includearrows on communication paths to show a primary direction ofcommunication, it is to be understood that communication may occur inthe opposite direction to the depicted arrows.

Many variations and modifications can be made to the embodiments withoutsubstantially departing from the principles of the present inventiveconcepts. All such variations and modifications are intended to beincluded herein within the scope of present inventive concepts.Accordingly, the above disclosed subject matter is to be consideredillustrative, and not restrictive, and the appended examples ofembodiments are intended to cover all such modifications, enhancements,and other embodiments, which fall within the spirit and scope of presentinventive concepts. Thus, to the maximum extent allowed by law, thescope of present inventive concepts are to be determined by the broadestpermissible interpretation of the present disclosure including thefollowing examples of embodiments and their equivalents, and shall notbe restricted or limited by the foregoing detailed description.

The invention claimed is:
 1. A method by a coordination node forcontrolling communications between Light Fidelity, Li-Fi, Access Points,APs, and user equipments, UEs, the method comprising: receiving peerconnectivity reports from Li-Fi APs which identify Li-Fi APs having atleast partially overlapping coverage areas; developing a handoverpathway data structure, based on the peer connectivity reports, thatidentifies Li-Fi APs that can receive communication handover from otheridentified Li-Fi APs; determining an identifier of a first Li-Fi APproviding Li-Fi communication service for a UE; accessing the handoverpathway data structure using the identifier of the first Li-Fi AP todetermine an identifier of a second Li-Fi AP to which handover from thefirst Li-Fi AP can be performed; and initiating handover of the Li-Ficommunication service for the UE from the first Li-Fi AP to the secondLi-Fi AP.
 2. The method of claim 1, wherein developing the handoverpathway data structure, comprises: determining an identifier of areporting Li-Fi AP that reported one of the peer connectivity reports tothe coordination node; determining an identifier of one or more observedLi-Fi APs based on content of the one of the peer connectivity reports;and storing in the handover pathway data structure the identifier of theone or more observed Li-Fi APs with a logical association to theidentifier of the reporting Li-Fi AP.
 3. The method of claim 2, whereindetermining an identifier of a first Li-Fi AP providing Li-Ficommunication service for a UE, comprises: receiving a report containinga measurement by the UE of a Li-Fi signal received from the first Li-FiAP; responsive to determining that the measurement does not satisfy asignal quality threshold, performing the initiating handover of theLi-Fi communication service for the UE from the first Li-Fi AP to thesecond Li-Fi AP.
 4. The method of claim 2, wherein: the one of the peerconnectivity reports contains pairs of an identifier of one of the oneor more observed Li-Fi APs and a measurement by the reporting Li-Fi APof a Li-Fi signal received from the one of the one or more observedLi-Fi APs; and selectively performing the storing in the handoverpathway data structure the identifier of the observed Li-Fi AP with alogical association to the identifier of the reporting Li-Fi AP, only ifthe measurement by the reporting Li-Fi AP of the Li-Fi signal receivedfrom the one of the one or more observed Li-Fi APs satisfies a signalquality threshold.
 5. The method of claim 4, wherein the identifier ofthe one of the one or more observed Li-Fi APs is selectively stored inthe handover pathway data structure with a logical association to theidentifier of the reporting Li-Fi AP, only if at least one of thefollowing conditions is satisfied: 1) a signal strength indicated by themeasurement satisfies a signal strength threshold; and 2) a bit errorrate indicated by the measurement satisfies a bit error rate threshold.6. The method of claim 2, wherein: the one of the peer connectivityreports contains pairs of an identifier of one of the one or moreobserved Li-Fi APs and a measurement by the reporting Li-Fi AP of aLi-Fi signal received from the one of the one or more observed Li-FiAPs, and the pairs are stored in the handover pathway data structurewith a logical association to the identifier of the reporting Li-Fi AP;and responsive to when the accessing of the handover pathway datastructure using the identifier of the first Li-Fi AP identifies aplurality of candidate Li-Fi APs, the second Li-Fi AP is selected fromamong the candidate Li-Fi APs based on comparison of the measurementsassociated with the candidate Li-Fi APs which are retrieved from thehandover pathway data structure.
 7. The method of claim 2, whereindeveloping the handover pathway data structure further comprises:subsequent to the storing, determining that an absentee one of theobserved Li-Fi APs has not been identified in a peer connectivity reportreceived from the reporting Li-Fi AP in at least a threshold elapsedtime; and removing from the handover pathway data structure theidentifier of the absentee one of the observed Li-Fi APs and its logicalassociation to the identifier of the reporting Li-Fi AP.
 8. The methodof claim 1, wherein determining the identifier of the first Li-Fi APproviding Li-Fi communication service for the UE, comprises parsing ahandover request message received from the first Li-Fi AP to determinethe identifier of the first Li-Fi AP.
 9. The method of claim 1, whereinthe initiating handover of the Li-Fi communication service for the UEfrom the first Li-Fi AP to the second Li-Fi AP, comprises: initiatingre-routing of data packets that are addressed to the UE, to be directedto the second Li-Fi AP instead of to the first Li-Fi AP.
 10. The methodof claim 1, wherein the initiating handover of the Li-Fi communicationservice for the UE from the first Li-Fi AP to the second Li-Fi AP,comprises: coordinating negotiations between the first and second Li-FiAPs to perform the handover of the Li-Fi communication service for theUE.
 11. The method of claim 1, further comprising: responsive to anaccess of the handover pathway data structure resulting in return of noidentifier of another Li-Fi AP as having been defined as associated withthe identifier of the first Li-Fi AP, initiating handover of the Li-Ficommunication service for the UE from the first Li-Fi AP to a group ofLi-Fi APs at least one of which that is likely to have a coverage areathat includes the UE.
 12. A coordination node for controllingcommunications between Light Fidelity, Li-Fi, Access Points, APs, anduser equipments, UEs, the coordination node comprising: a networkinterface; a processor coupled to the network interface; and a memorycoupled to the processor and storing program code that when executed bythe processor causes the processor to perform operations comprising:receiving peer connectivity reports from Li-Fi APs which identify Li-FiAPs having at least partially overlapping coverage areas; developing ahandover pathway data structure, based on the peer connectivity reports,that identifies Li-Fi APs that can receive communication handover fromother identified Li-Fi APs; determining an identifier of a first Li-FiAP providing Li-Fi communication service for a UE; accessing thehandover pathway data structure using the identifier of the first Li-FiAP to determine an identifier of a second Li-Fi AP; and initiatinghandover of the Li-Fi communication service for the UE from the firstLi-Fi AP to the second Li-Fi AP.
 13. A method by a Light Fidelity,Li-Fi, Access Point, AP, for communicating with user equipments, UEsunder control of a coordination node, the method comprising: receivingLi-Fi signals from observed Li-Fi APs, the Li-Fi signals providingidentifiers of the observed Li-Fi APs; generating a peer connectivityreport containing an identifier of the Li-Fi AP and the identifiers ofthe observed Li-Fi APs; and reporting the peer connectivity report tothe coordination node, wherein generating the peer connectivity reportfurther comprises: subsequent to the reporting of the peer connectivityreport to the coordination node, determining that a Li-Fi signal has notbeen received from one of the observed Li-Fi APs contained in the peerconnectivity report in at least a threshold elapsed time; and excludingthe one of the observed Li-Fi APs from another peer connectivity reportthat is next reported to the coordination node responsive to thedetermination.
 14. The method of claim 13, further comprising: receivingfrom a UE measurements by the UE of Li-Fi signals transmitted by theLi-Fi AP and other Li-Fi APs; and reporting an indication of themeasurements in the peer connectivity report.
 15. The method of claim13, further comprising: measuring a Li-Fi signal received from a UEduring Li-Fi communication service by the Li-Fi AP for the UE; andincluding an indication of the measurement in the peer connectivityreport reported to the coordination node.
 16. The method of claim 13,further comprising: receiving from a UE measurements by the UE of aLi-Fi signal transmitted by the Li-Fi AP; and sending a handover requestto the coordination node responsive to the measurement not satisfying asignal quality threshold.
 17. The method of claim 13, furthercomprising: receiving a handover message from the coordination node; andperforming handover of Li-Fi communication service for a UE from theLi-Fi AP to one of the observed Li-Fi APs that is identified by thehandover message.
 18. The method of claim 13, further comprising:measuring the Li-Fi signals received from the observed Li-Fi APs; andgenerating the peer connectivity report to further contain themeasurements with defined associations to the identifiers of theobserved Li-Fi APs.
 19. A Light Fidelity, Li-Fi, Access Point, AP, forcommunicating with user equipments, UEs under control of a coordinationnode, the Li-Fi AP comprising: a network interface; a processor coupledto the network interface; and a memory coupled to the processor andstoring program code that when executed by the processor causes theprocessor to perform operations comprising: receiving Li-Fi signals fromobserved Li-Fi APs, the Li-Fi signals providing identifiers of theobserved Li-Fi APs; generating a peer connectivity report containing anidentifier of the Li-Fi AP and the identifiers of the observed Li-FiAPs; and reporting the peer connectivity report to the coordinationnode, wherein generating the peer connectivity report further comprises:subsequent to the reporting of the peer connectivity report to thecoordination node, determining that a Li-Fi signal has not been receivedfrom one of the observed Li-Fi APs contained in the peer connectivityreport in at least a threshold elapsed time; and excluding the one ofthe observed Li-Fi APs from another peer connectivity report that isnext reported to the coordination node responsive to the determination.